Field of the Invention
This invention relates to a glazed wall intended to separate a room from the outside in which a glazing is heated electrically and where air circulates along the heated glazing before being distributed in the air of the room.
It is known to improve the performance of a glazed wall separating a heated room from the outside environment by forming this wall with double transparent panes or plates and making air circulate between the two panes, the air often being drawn from the outside and then mixed with air from the room. Many such systems have been proposed. Their advantage resides in the fact that the heat loss is reduced relative to that of the same wall without such air circulation but with direct introduction of outside air.
Nevertheless, with known walls, because at least one part of the air which circulates along the inside glazing is drawn from outside the building, the temperature of the inside glazing remains lower than that of the internal partitions of the building which constitute the other walls of the room. As a result, the space in the vicinity of the outside wall is relatively cold and its use is generally limited. It would be advantageous to be able to raise the surface temperature of this wall. It has been proposed to do so by insulating it more, for example by replacing the simple inside glazing with a double pane insulating glazing. Comfort is thus improved but the replacement air which runs along the wall is then heated less and the overall heat balance is not appreciably improved.
It has been thought to improve the situation by directly using the heat supply for heating the room to increase the surface temperature of the glazing which constitutes the inner face of the glazed wall separating the room from the outside. European patent EP 102 987 B thus proposes heating the replacement air before its passage along the wall. This system is satisfactory but a part of the energy supplied is used for needlessly reheating the outside wall.
A variant of the preceding system in which one of the glazings constituting the wall itself is heated has also been proposed. Generally, in this case, a transparent conducting layer consisting of a thin layer of metal deposited under vacuum is used. Such a system exhibits obvious advantages since the supply of heat is there where it is the most useful, to the room itself, and it makes it possible to incorporate additional functions into the glazed wall, i.e., both natural lighting and air replacement and heating.
However, the energy loss of this known system is significant. The heat exchange between the two glazings constituting the wall, i.e., the inner heated glazing and the outer glazing at a lower temperature, is considerable. For this reason, in U.S. Pat. No. 4,641,466, it was proposed that the glazing opposite the heated glazing be equipped with a layer capable of reflecting infrared rays so as to send back the heat radiation emitted by the heated glazing, thus reducing the escape of heat.
Various devices also are known which make possible the use of heated glazings under good operating conditions. Thus, for example, European Patent application EP 165287 proposes regulation of the glazing temperature and, like French patent FR 2 180 433, an automatic cutoff of the power supply when it becomes unnecessary or dangerous to maintain it.
But these latter glazed walls, although they exhibit advantageous technical solutions, are complicated and consequently difficult to use and, generally, are expensive.